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Soft Starter 60A STB060

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The STB soft starter is designed to smoothly start (and stop) 3 phase induction motors. By employing a timed voltage ramp system (open loop control) you have greater control over soft-start and soft-stop performance reducing energy costs and enhancing the efficiency of your motor..

Availability: In stock

Excl. Tax: £526.50 Incl. Tax: £631.80

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Excl. Tax: £526.50 Incl. Tax: £631.80
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Product Description


With a built-in bypass function and simple operation, the STB range from CD Automation offers a compact, cost effective solution to start and stop 3 phase AC motor control.

A soft starter is a device which controls the acceleration of an electric ac motor by means of controlling the applied voltage.

Without this control the interaction between the rotating magnetic field flux and the rotor winding flux will result in a high rotor current as torque is increased. By the time the motor reaches full speed, a current greater than the rated current will be drawn resulting in overheating and likely motor damage. To prevent this, a soft starter is needed.

Suitable for Squirrel Cage Motors the STB060 soft-starter works by gradually applying reduced voltage, essential in protecting the motor from overheating causing winding damage (AC Motors that start at full voltage can experience 5 to 9 times their nominal current).

Three adjustments can be made on the STB060 soft starter:

  • Initial start voltage (initial torque).
  • Soft start ramp time (ramp up).
  • Soft stop ramp time (ramp down).

No feedback is needed from the motor and Ramp-up and Starting (Initial) Torque is set by the operator from the STB’s front panel.

While soft starters operate continuously to control and protect the motor, the soft starter power section may be bypassed once the soft start is complete. This built-in bypass function provides greater operating efficiency and reduced heat in the enclosure (eliminating additional enclosure cooling).

In addition, the STB range has a kick start facility. The kick start allows the motor to draw greater current at start-up and create additional torque to break away a high friction load, useful in starting blocked pumps etc. This feature is user selectable between 100, 200 and 300mS.

Specification, Dimensions & Downloads

Additional Information

Starter Guide


Product Manual


Product Videos No

Soft Starter 60A STB060

Mains Supply  
Mains voltage (L1, L2, L3) STB-006-2 3 x 208Vac to 240Vac max. (+10% / -15%)
Mains voltage (L1, L2, L3) STB-006-4 3 x 400Vac to 480Vac max. (+10% / -15%)
Mains frequency (at start) 47 Hz to 70 Hz
Rated insulation voltage 600 VAC
Operating maximum current 60A AC3
Maximum start current
Leakage current 10mA
Minimum working current 1000mA
Starts per hour 6
Motor rating 240V 25.6 HP / 19.1kW
Motor rating 480V 44.5 HP / 33.2kW
Ramp time 2 to 20 seconds
Kick start at 70% (set by dip switch) 0, 100, 200, 300mS
Initial torque 30 to 70%
Control Input  
Manual Start/Stop (terminals 4 & 5) 4 = ground 4 to 24Vac/dc
Automatic Start/Stop Auto start on power up
Main contactor relay (terminals 1, 2, 3) NC, NO, C Max. 500mA, 125Vac
Degree of protection IP20
Operating temperature 0°C to +40°C
Storage temperature -25°C to +70°C
Humidity 5% to 95% Relative Humidity
Standards met  
Low-voltage switchgear and controlgear. Contactors and motor-starters. AC semiconductor controllers and contactors for non-motor loads
Electrical Safety Standard EN6097-1:2008
Generic Emission Standard EN6097-4-3:2000
Generic Immunity Standard EN6097-4-3:2000


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